div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: Safety control src=https:reader035vdocumentsnetreader035viewer2022081213575068831a28ab0f07b0823ahtml5thumbnails1jpg width=142 height=106 layout=responsive amp-img divp© 1991 Nature Publishing Grouppdiv